Adobe says the folder for installing the new beta profiles for Nikon D810 on Windows is 'C:\Users\[user name]\AppData\Roaming\Adobe\CameraRaw\CameraProfiles.
But I can only get as far as C:\Users\[user name]\Application Data - i.e. no folder named Roaming.
Have you enabled the Viewing of all hidden folders in Windows?
That's the solution. Great, thanks.